A High-frequency Motor Model Constructed Based on Vector Fitting Method

Electric drive system is a key indicator that distinguishes the electric vehicles from traditional vehicles, and it is a technical innovation of energy generation and distribution. Compared to the traditional mechanical drive system, high-voltage components such as inverter, drive-motor, battery pack are equipped in the electric drive system. During the driving, the switching behavior of power components will produce high amplitude and wide band electromagnetic interference. It is necessary to construct a system-level EMC model to predict the electromagnetic interference, and thus help the EMC engineer to optimize the system EMC design. This paper proposes a high-frequency motor modeling method, which firstly uses the vector fitting method to fit the motor impedance characteristic to a rational expression with series of pole-residue pairs, and then transfers it to a circuit model. In this paper, the high-frequency modeling of a 140kW permanent magnet synchronous motor is carried out by the above method. The accuracy of the model is verified by comparison with the test data.